Apparatus and method for cardiac stabilization and arterial occlusion

ABSTRACT

An apparatus and method of use is provided for locally stabilizing an anastomotic site during a beating heart surgical procedure which includes occluding a section of the artery receiving the bypass graft vessel. An apparatus is provided to stabilize the epicardium and the operational field, and includes a platform that can be compressed onto the epicardium or tensioned by pulling the epicardium upwardly, thereby providing a stabilized operational field. At least one occluding member provides means to occlude the section of artery receiving the bypass graft vessel. An adjustable stabilizing arm can be used in conjunction with the platform to further provide stability to the epicardium during the beating heart bypass graft procedure.

This application is a continuation of application Ser. No. 08/857,428filed May 16, 1997, U.S. Pat. No. 5,957,835.

BACKGROUND OF THE INVENTION

The invention relates generally to a system and method of stabilizing apatient's beating heart during a medical procedure, such as coronaryartery bypass grafting (CABG). More specifically, the invention relatesto an apparatus and method for stabilizing the epicardium and occludingthe section of the artery to receive a graft vessel.

In a typical CABG procedure on a stopped heart, the patient undergoes amedian sternotomy to provide access to the heart area and is put oncardiopulmonary bypass equipment (CPB) to oxygenate the blood and allowthe heart to be stopped. These procedures are well known, are safe andare widely accepted for a wide range of medical procedures performed onthe heart. A more thorough discussion of a typical CABG procedure can befound in Manual of Cardiac Surgery, Second Edition, by Bradley J.Harlan, MD, Albert Starr, MD and Fredric M. Harwin, BFA, MS, 1995, and adiscussion of open heart procedures can be found in Textbook ofInterventional Cardiology, Eric J. Topol, 1990, chapters 43-44, pages831-867, incorporated herein by reference.

It should be understood that while the foregoing CABG procedures aregenerally regarded as safe and widely accepted, they are not withoutrisks. As is known, when the patient is put on cardiopulmonary bypassequipment, the blood is continuously pumped extracorporeally where it isoxygenated and then returned to the body. Any time the blood is removedfrom the body there is the risk of infection such as sepsis or otherinfections that can be serious if not detected and treated. During theoxygenation process, micro-emboli are introduced that are believed to bea major cause of neurological damage which can be temporary orpermanent. While the heart and lungs are being bypassed, the heart isinfused with cardioplegic fluid to stop the heart from beating and limitdamage to the muscle cells due to lack of blood. However, the lungs arenot perfused with blood for many hours and this can cause many problems.Also, there is a need to prime the CPB pump with about one liter offluid. This fluid is pumped into the patient's body in the first fewseconds of CPB resulting in a hemodilution of about 20%. As the blood istransported through many feet of tubing and various oxygenators, heatexchangers, and pumps, it is in contact with foreign materials. Thiscontact induces compliment activation which can lead to pulmonarydysfunction, renal dysfunction and further embolic complications.Further, the equipment needed to perform cardiopulmonary bypass isexpensive and requires specialized medical personnel to operate andmonitor.

During coronary artery bypass procedures using the beating heartapproach, the region of the heart which receives the graft vessel mustbe stabilized so that the graft and suturing procedure can be performedon a substantially stationary epicardium. Presently, this is oftenperformed by threading two sutures through the myocardium with curvedneedles, on either side of the recipient coronary artery at the site ofthe anastomosis. The sutures are tensioned to lift the heart and to holdthe coronary artery stationary. Suture threads with curved needlesswaged on one end are available for this use. Also, suture threads maybe used to loop around and tighten the section of artery to be grafted,thereby occluding the artery during the procedure. Again, with the heartbeating, placing these suture loops around the artery is difficult dueto the movement of the heart and the epicardium surrounding the artery.

Placement of the suture loops may be somewhat difficult, as the heart isbeating. The tip of the needle must be placed on the heart, and rotationof the surgeon's wrists must be performed to insert the needle throughthe myocardium or epicardium. Unpredictable motion of the epicardialsurface during needle placement may cause laceration of the heart,puncture of the wall into the ventricle, or puncture of a coronaryartery. It is therefore useful to stabilize the anastomotic area duringthe surgical procedure. There are devices and methods that facilitatethe performance of cardiac procedures such as heart valve repair andreplacement, coronary artery bypass grafting, and the like, usingminimally invasive techniques to eliminate the need for a grossthoracotomy. For example, U.S. Pat. No. 5,425,705 to Evard et al.discloses an apparatus and method for thoracoscopically arresting theheart and establishing cardiopulmonary bypass, thus facilitating avariety of less-invasive surgical procedures on and within the heart andgreat vessels of the thorax. In one embodiment, Evard provides athoracoscopic system for arresting a patient's heart including a clampconfigured for introduction into the patient's thoracic cavity through apercutaneous intercostal penetration in the patient's chest. The clampis positionable about the patient's ascending aorta between the coronaryarteries and the brachiocephalic artery. The clamp is coupled to thedistal end of an elongated handle for manipulating the clamp from alocation outside of the patient's thoracic cavity.

It is known to use surgical clips or clamps for the purpose of clampingvessels or manipulating tissue. Typically, such clamps have a pair ofmovable jaws biased by a spring into a closed position, allowing theclamp to be placed on a vessel or portion of tissue and be firmlyretained thereon. Examples of such clamps can be found in U.S. Pat. No.4,932,955 to Merz et al.; U.S. Pat. No. 4,605,990 to Wilder et al.; U.S.Pat. No. 5,074,870 to Von Zeppelin; U.S. Pat. No. 3,809,094 to Cook;U.S. Pat. No. 4,404,677 to Springer; U.S. Pat. No. 4,051,844 to Chiulli;and U.S. Pat. No. 4,988,355 to Leveen et al.

Outside of the field of cardiac surgery, U.S. Pat. No. 5,415,666 toGourlay et al. discloses a tethered clamp retractor used for tissuemanipulation. The tissue manipulation system includes a tethered clamp,a clamp applicator for positioning the clamp through a trocar sleeve andapplying the clamp to a tissue location in the abdominal cavity, and arigid positioning shaft for engaging the clamp and/or tether tomanipulate the clamp.

In view of the shortcomings of the prior art devices, there is aspecific need for an apparatus and method for locally stabilizing ananastomotic site during a beating heart coronary artery graftingprocedure. What has been needed and heretofore not available is a methodof stabilizing the beating heart during a medical procedure withouthaving to perform CPB and subjecting the patient to the attendant risksand complications. The present invention solves the problems of theprior art methods without the resulting risks.

SUMMARY OF THE INVENTION

The present invention is directed to an apparatus and method of use forlocally stabilizing an anastomotic site of a beating heart during acardiac surgical procedure, and occluding a section of artery to receivea bypass graft. More specifically, an apparatus is provided to stabilizethe epicardium in an area referred to herein as the operational field,which includes the area where a section of a coronary artery receives abypass graft. The invention further includes means for occluding theartery during the bypass grafting procedure.

The invention includes a platform having a top surface and a bottomsurface, with at least a portion of the bottom surface configured forcontacting the epicardium of the heart. A pair of occluding members areconfigured for slidable and vertical movement within the platform forpositioning over and occluding a section of artery. The platform can besutured or otherwise attached to the epicardium thereby defining anoperation field within the platform on the epicardium, and stabilizingthe epicardium within the operational field. By temporarily attachingthe platform to the epicardium, a slight tensioning or stretching of theepicardium occurs which results in a stabilizing effect around theplatform. The occluding members are positioned over and into contactwith the epicardium surface over the artery, and temporarily locked inplace thereby temporarily occluding a section of artery in theoperational field.

In one embodiment, the platform has a substantially U-shapedconfiguration for defining the operational field. The platform includesa pair of legs connected by a connecting member, with the legs eachhaving a slot in which the occluding member is retained for slidablemovement. The connecting member can be adjustable so that the distancebetween the legs can be adjusted, thereby adjusting the size of theoperational field that is stabilized during the grafting procedure.Alternatively, the connecting member can be malleable thereby permittingthe legs to be pivoted, thereby adjusting the distance and angle betweenthe legs so that they can be more easily positioned over the artery tobe occluded.

One advantage of the present invention is to provide occluding membersthat are slidably adjustable within the slots of the legs in theplatform. The occluding members can be adjusted so that they can bepositioned over the section of artery to be grafted and then temporarilylocked in place by twisting the members into locking engagement with theslots.

In one embodiment, to assist in further stabilizing the operationalfield, an adjustable arm having a first end for removable attachment tothe top surface of the platform is provided. The adjustable arm has asecond end for removable attachment to a support that is stationaryrelative to the platform. Typically, the stationary support can includea rib retractor on which the second end of the adjustable arm isclamped.

In the preferred method of stabilizing the epicardium and occluding thesection of artery to be grafted, the platform is positioned over theartery to be grafted. The platform can be sutured in place or attachedby other means, generally if the adjustable arm is not attached. Oncethe platform is attached to the epicardium, the area becomes stabilizedso that the occluding members can be positioned over the artery andlocked into engagement in the slots, thereby occluding the artery. Themedical procedure is then performed, wherein a vessel is grafted in anend-to-side grafting procedure which is known in the art. After themedical procedure is performed, the platform is removed from theepicardium.

In an alternative method, the platform with the adjustable arm attachedis positioned on the epicardium and the second end of the adjustable armis temporarily attached to the stationary support. The adjustable arm,since it is flexible, can be used to position the platform and slightlycompress the platform onto the epicardium, whereby the adjustable arm isthen locked so that it is rigid. In the locked position, the adjustablearm is substantially rigid and applies slight compressive force to theplatform, thereby stabilizing the epicardium. Alternatively, theadjustable arm can be used to pull the platform, which is attached tothe epicardium, upwardly thereby tensioning and stabilizing theoperational field. Thereafter, the occluding members are positioned overthe artery and locked into place in the slots in order to occlude theartery during the grafting procedure. After the grafting procedure iscompleted, the adjustable arm is unlocked, thereby returning the arm toflexibility, and the device is removed from the patient.

Other features and advantages of the invention will become apparent fromthe following detailed description, taken in conjunction with theaccompanying drawings which illustrate, by way of example, the featuresof the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of the platform used to stabilize the epicardium.

FIG. 2 is a side elevational view depicting the platform of FIG. 1 usedto stabilize the epicardium.

FIG. 3 is a top view depicting the platform wherein the connectingmember for the legs is adjustable.

FIG. 4 is a top view of the platform wherein the connecting member ismalleable so that the legs can be adjusted.

FIG. 5 is an elevational view depicting the platform wherein theoccluding member is positioned over an artery.

FIG. 6 is an elevational view of the platform positioned on theepicardium with the occluding member in contact with and occluding theartery.

FIG. 7 is an elevational view of the platform depicting the occludingmembers at an angle to provide easier access to the operational field.

FIG. 8 is a front elevational view of the elongate body which forms partof the occluding member.

FIG. 9 is a side elevational view of the elongate body of FIG. 8 turned90°.

FIG. 10 is cross-sectional view depicting a body portion for receivingthe elongate member thereby forming the occluding member.

FIG. 11 is an elevational view of the body portion of FIG. 10.

FIG. 12 is a front elevational view of the body portion depicting theoccluding end which contacts the artery.

FIG. 13 is a cross-sectional view of the body portion of FIG. 12,depicting the recess for receiving the elongate body of FIGS. 8 and 9.

FIG. 14 is an elevational view of an alternative embodiment of the rigidelongate core.

FIG. 15 is a front elevational view of an alternative embodimentdepicting the body portion of the occluding member, further depictingthe more circular occluding end for contacting the coronary artery.

FIG. 16 is a top elevational view of the platform depicting angulatedslots.

FIG. 17 is a front elevational view depicting the platform of FIG. 16,in which the angulation of the slots are more clearly depicted.

FIG. 18 is an elevational view of an adjustable arm for use inconjunction with the platform.

FIG. 19 is a cross-sectional view of a link associated with theadjustable arm.

FIG. 20 is a top elevational view of the adjustable arm connected to arib retractor.

FIG. 21 is a top elevational view of the platform positioned on theepicardium of the heart and further depicting the occluding members incontact with a section of the artery to receive a bypass graft vessel.

FIG. 22 is a top elevational view depicting the platform being connectedto the adjustable arm.

FIG. 23 is a top elevational view depicting the platform attached to theadjustable arm, further depicting the platform being positioned on theepicardium and the occluding members occluding a section of an artery.

FIG. 24 is an elevational view of a wire retractor for use with theplatform stabilizing invention.

FIG. 25 is a perspective view of the platform positioned on theepicardium depicting the retractor of FIG. 24 used to pull back theepicardium to expose the arteriotomy site.

FIG. 26 is a perspective view of the platform positioned on theepicardium, depicting the retractor of FIG. 24 positioned through a slotin the platform and holding back the epicardium to expose thearteriotomy site.

FIG. 27 is a perspective view of the platform further depicting analternative embodiment of the occluding members for occluding theartery.

FIG. 28 is a partial view of one leg of the platform, in perspective,depicting a carriage for slidable movement along the leg.

FIG. 29 is an end elevational view, partially in cross-section, of theleg and carriage assembly of FIG. 28, with the occluding member retainedin the carriage member.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides an apparatus and method for use forstabilizing the epicardium of a beating heart during a cardiac surgicalprocedure, such as bypass grafting, and to occlude a section of arteryreceiving the bypass graft vessel. The apparatus of the inventionstabilizes the epicardium in the operational field, which includes thearea where a section of a coronary artery receives a bypass graftvessel. The invention further includes the apparatus and method foroccluding a section of the artery where the bypass graft procedureoccurs.

In keeping with the invention, as shown in FIGS. 1-4, platform 10 has aU-shaped configuration which includes first leg 11 and second leg 12 insubstantially parallel relationship and spaced apart. The first andsecond legs are connected by connecting member 13 which, in FIGS. 1 and2, is a rigid member which maintains the first and second legs in aparallel relationship. Platform 10 also includes top surface 14 andbottom surface 15, where at least a portion of the bottom surface isconfigured for contact with the epicardium of the heart.

As depicted in FIG. 2, bottom surface 15 of the platform is concave.First concave portion 18 is provided so that when the bottom surface ofthe platform is pressed onto the epicardium or attached to theepicardium, in the area of a coronary artery, the concave portion ispositioned over the coronary artery so that it does not inadvertentlyocclude the artery. As will be described herein, means are provided tointentionally occlude a section of the artery, however, it is notintended that the platform itself, and importantly the bottom surfaceinadvertently occlude a portion of artery during the medical procedure.The radius of concave portion 18 can vary depending upon theapplication, and may range from approximately 3 inches to about 12inches. Preferably, the radius of concave portion 18 is approximately 8inches. It also may be desirable to provide second concave portion 19that has a smaller radius than the first concave portion. The secondconcave portion can then be positioned over the artery without occludingit. The second concave portion 19 has a radius in the range of about 0.5to 3.0 inches and preferably is about 1.3 inches.

The area encompassed by the boundaries of first leg 11, second leg 12and connecting member 13 define operational field 20. If it is desiredto provide a larger or smaller operational field, the dimensions ofplatform 10, and specifically the distance between first leg 11 andsecond leg 12 can be varied to suit the particular application. In orderto provide flexibility for the surgeon performing the bypass procedure,it may be desirable to vary the size of the operational field 20 duringthe procedure. Depicted in FIGS. 3 and 4, the distance and angle betweenfirst leg 11 and second leg 12 is adjustable. In FIG. 3, connectingmember 13 can be a two-piece member, one slidable within the other in atelescoping manner, so that the distance between the first leg and thesecond leg can be varied, while the legs remain parallel to each other.The platform depicted in FIGS. 1-3 can be formed of a rigid materialincluding metal alloys, stainless steel, polycarbonate, Ultem® (Ultem®is available from General Electric Plastics, Pitsfield, Mass.) or rigidpolymers. Importantly, the materials must be biocompatible, andpreferably sterilizable, however, the platform is configured anddesigned for single use applications and would not require furthersterilization after a single procedure.

Referring to an alternative embodiment of platform 10, as shown in FIG.4, connecting member 13 is formed from a malleable material, whichprovides flexibility so that first leg 11 and second leg 12 can beessentially pivoted apart to increase or decrease the size ofoperational field 20. Examples of malleable materials include amalleable wire made from 304 stainless steel wire covered with apolymer, such as polyethylene, urethane, and silicone.

Since the function and purpose of platform 10 is to providestabilization of the epicardium in the operational field, it is intendedthat it be used either alone, or in conjunction with further apparatusas will be described herein. When used alone, it may be desirable totemporarily attach platform 10 to the epicardium. In that regard, asdepicted in FIGS. 1-4, a plurality of grooves 21 are provided on topsurface 14. The grooves are indentations for receiving a suture threadthat is passed through the epicardium with a needle or other means, andpositioned in the groove and tightened so that the platform can besutured to the epicardium. In the specific embodiments depicted in thedrawings, there are four grooves 21 for receiving sutures, therebyproviding four attachment points on platform 10. At least threeattachment points are preferred, and more attachment points may bedesired. With at least three attachment points between platform 10 andthe epicardium, operational field 20 can be placed in tension, whichprovides stabilization. More or less grooves 21 can be provided, and itis contemplated that other attachment means can be substituted for thegrooves, including apertures passing through platform 10, tabs attachedto the sides or top of the platform, and similar attachment means. Inaddition, in some circumstances suture threads may not be ideal and itmay be desirable to use other attachment means such as hooks, screws orhelical fasteners. For example, hooks on the sides of platform 10 or onbottom surface 15 may be used as attachment points. Further, helicalscrews such as the Origin Tacker®, manufactured and sold by OriginMedSystems, Menlo Park, Calif., can be used to attach platform 10 to theepicardium. The attachment means is biocompatible and in the case ofsuture threads, helical screws, and similar attachment means, they arebioabsorbable and will be absorbed into the body over a short period oftime.

While dimensions may vary depending upon a particular application, in apreferred embodiment the distance between first leg and second leg is inthe range of approximately 0.2 to 2.0 inches. The length of legs 11, 12also will vary depending upon the application, and preferably are in therange of about 0.5 to 3.5 inches. In the embodiments depicted in FIGS. 3and 4, the distances between the legs can be varied by the surgeon atthe time of the procedure.

The platform may be adapted to include means for occluding a section ofthe artery to be grafted so that the platform provides not only astabilization function, but an occluding function during the bypassprocedure. As depicted in FIGS. 1, 3-7 16-17, and 21-23, the platformincludes a pair of slots and movable occluding members for occluding theartery.

In a preferred embodiment, platform 10 includes first slot 30 and secondslot 31 in first leg 11 and second leg 12 respectively. The slots areconfigured for receiving first occluding member 32 in first slot 30 andsecond occluding member 33 in second slot 31. The occluding members32,33 are configured for slidable movement within the slot and verticalmovement into and out of engagement with either the artery, or theepicardium directly above the artery so that the first and secondoccluding members can occlude the artery during the bypass procedure.

First and second occluding members 32,33 are slidably retained in firstslot 30 and second slot 31, respectively, so that the occluding memberscannot be removed from the slot without substantial force being applied.While it is intended that the occluding members freely slide in the slotand move vertically, it is equally important that they not beinadvertently removed from the slot during the medical procedure for theprotection of the patient. Thus, by design, occluding members 32,33cannot easily be removed from slot 30,31. In an alternative embodiment,occluding members 32,33 may be tethered to platform 10 for positioningin slots 30,31 during the bypass procedure.

As will be more fully described herein, as depicted in FIGS. 5 and 6,first and second occluding members 32,33 are moved from parked position34 where they are out of the surgeon's way at the beginning of thebypass procedure, to engagement position 35, whereby the occludingmembers are moved into contact with the artery or the epicardiumdirectly above the artery.

Platform 10 can be designed for use with only a single occluding member,which may be desirable under certain conditions. With two occludingmembers projecting upwardly from the surface of platform 10, it mayreduce the ability of the surgeon to perform certain of the bypassprocedures. It may be desirable to use only one occluding member toocclude the section of the artery under conditions where operating spaceis tight. Also, under circumstances where the artery being grafted istotally occluded, it may unnecessary to use two occluding members sincethe upstream portion of the artery already is occluded. In keeping withone preferred embodiment of the invention, as depicted in FIGS. 7 and16-17, it may be desirable to angulate slots 30,31 so that occludingmembers 32,33 also are angulated. In this embodiment, the occludingmembers are angulated so that they provide easier access to theoperational field, since they are more out of the way than if the slotsare perpendicular in the platform. Thus, first angle is provided so thatoccluding members 32,33 are angulated thereby exposing greater access tooperational field 20. Preferably, slots 30, 31 include first angle 36,measured from the vertical, in the range of about 5° to 45°, and morepreferably in the range of about 20° to 30°. The top surface 14 of slots30, 31 also are angulated, as indicated by second angle 37, preferablysecond angle 37°, measured from the horizontal, is in the range of about0° to 30°, and more preferably in the range of 10° to 22°.

As depicted in FIGS. 8-15, several embodiments of first and secondoccluding members 32,33 are depicted. The occluding members includerigid elongate core 40 having tab 41 at one end, shaft 42 extending fromtab 41, and flange 43 located on the shaft. Core 40 is intended to beformed from a metal or metal alloy, such as stainless steel, or a rigidpolymer material. Occluding members 32, 33 also comprise body portion 44having slot 45 for receiving shaft 42. Body portion 44 also includesoccluding end 46 configured for direct engagement with the artery, orthe epicardium directly above the artery. The occluding end and bodyportion can be formed from various materials, including silicone,urethane, polycarbonate, and polypropylene. Other similar materials alsomay be suitable.

In one embodiment, as depicted in FIGS. 12 and 13, occluding end 46provides an atraumatic contour so that when contacting the artery orepicardium, it does not damage or tear any portion of the artery or theepicardium.

In a preferred embodiment as depicted in FIGS. 8-13, elongate core 40 isinserted into slot 45 of body portion 44. Flange 43 locks into recess 47in the body portion thereby providing an interference fit, making itextremely difficult to remove core 40 from portion 44.

As can be seen in FIG. 11, body portion 44 includes retainer 48 which isconfigured to substantially match the configuration of first and secondslots 30, 31. Thus, retainer 48 allows first and second occludingmembers 32, 33 to slide within the slots. Preferably, shaft 42 has arectangular configuration as does slot 45. As will be described morefully herein, first and second occluding members 32, 33 must be lockedin position in first and second slots 30, 31. In order to lock theoccluding members in position, a twisting force is applied causing aninterference fit between the occluding members and the slots. In orderto provide sufficient locking force, shaft 42 and slot 45 arerectangular, as opposed to circular for example, so that the necessarytwisting or torquing action can be applied.

As depicted in FIGS. 14 and 15, the preassembled occluding members 32,33, include occluding end 46 that is more circular, rather thancontoured as depicted in FIGS. 12 and 13. The configuration of occludingend 46 is a matter of choice as long as it provides an atraumaticsurface to occlude the artery.

The platform also can be used in conjunction with an adjustable arm forstabilizing the epicardium. As depicted in FIG. 18, adjustable arm 60includes distal first end 61 and proximal second end 62. The adjustablearm 60 is flexible in one configuration and rigid in a secondconfiguration. Locking member 63 is located at second end 62 and isattached to threaded cable end 65 of cable 64. A locking ball 66 ispositioned at the distal end of the cable and in one position lockingmember 63 allows the cable to be flexible, while in a locked positionthe cable is tightened thereby providing a rigid adjustable arm. Theadjustable arm further includes a plurality of links 67, one of which isdepicted in FIG. 19. The links include a ball portion 68 whichessentially acts as a ball and socket joint with socket section 69 sothat the adjustable arm is flexible in the unlocked position. As can beseen in FIG. 20, adjustable arm 60 includes proximal clamp 70 which isadapted to releasably attach to, for example, rib retractor 71 or anyother similar stationary support in the operation area. At the oppositeend of the adjustable arm is a distal clamp 72 used to releasably attachto platform 10.

Both adjustable arm 60 and rib retractor 71 are known in the art andcommercially available. For example, an adjustable arm referred to asHUANG Universal Flexible Arm® is available from Codman and Shurtleff,Inc., Randolph, Mass. Rib retractors also are commercially available,one of which is ANKENEY Sternal Retractor, available from Codman andShurtleff, Inc., Randolph, Mass.

In keeping with the preferred method of using the invention, platform 10can be used with or without adjustable arm 60. As depicted in FIG. 21,platform 10 has been positioned on the epicardium and temporarilyattached thereto by suture threads 22. Once the suture threads have beentightened to temporarily attach the platform to the epicardium, theepicardium is tensioned thereby stabilizing the operational field. Atthis point, the artery is not occluded since first and second concaveportions 18, 19 on the bottom of the platform do not press down on theartery to restrict blood flow. While it is optional to use the occludingmembers of the invention to occlude the artery prior to performing thebypass procedure, other occluding means are available, including knownoccluding means such as looping a suture thread around the artery andtightening it to occlude the artery. In the preferred method of use, atleast the first occluding member 32 is moved from parked position 34 toengaged position 35 directly over the artery, and then presseddownwardly onto the artery or the epicardium directly over the artery toocclude the artery. With forceps or the surgeon's fingers, tab 41 istightly gripped and the first occluding member is twisted approximately90° so that it creates an interference fit within first slot 30. Theoccluding member now remains firmly wedged within the first slot andoccludes the artery for the surgeon to begin the grafting procedure.Preferably, the same procedure is employed to wedge the second occludingmember 33 in second slot 31 so that the section of artery between thefirst and the second legs 11,12 of the platform is completely occluded.The surgeon then performs the bypass graft procedure which is well knownin the art. Thereafter, the occluding members are released by twistingeach of them approximately 90° so that they are again slidably movablewithin the first and second slots. The suture threads are cut and theplatform is then removed from the patient.

In an alternative method of use embodiment, as depicted in FIGS. 22 and23, platform 10 is removably attached to adjustable arm 60. Distal clamp72 at the distal end of the adjustable arm is attached to hub 80 onplatform 10. The connection between distal clamp 72 and hub 80preferably provides for pivotal movement of the platform as can be seen,for example, in FIG. 2. While FIG. 2 does not show the attachment ofdistal claim 72 to hub 80, the pivoting motion is indicated by arrows81. The ability of platform 10 to pivot is advantageous due to thecontours of the heart and provides one more degree of adjustment in anoperating theater that is limited for space.

With adjustable arm 60 attached to platform 10, the platform is thenpositioned on the epicardium and temporarily attached thereto, by themeans herein described, such as by suturing, attachment hooks, helicalscrews, and the like. Proximal clamp 70 at the proximal end of theadjustable arm is then clamped onto rib retractor 71 or a similarstationary support. Thereafter, locking screw 63 engages threaded cableend 65 to tighten cable 64, thereby converting the flexible adjustablearm 60 to a rigid and stationary arm. Thus, platform 10 is nowstationary and if compressed onto the epicardium, provides a stabilizedoperating field. If desired, when adjusting the adjustable arm andlocking it into engagement so that it becomes rigid, it can be pulledupwardly away from the beating heart thereby placing the operationalfield in slight tension, as opposed to compression. In either direction,i.e., tensioning or compressing the platform onto the epicardium, willresult in stabilizing the operational field. Thus, the surgeon has theoption of tensioning or compressing the epicardium, depending upon theparticular application to benefit the patient.

With continued reference to FIGS. 22 and 23, the preferred methodincludes attaching the adjustable arm to the platform and temporarilysuturing the platform to the epicardium. Once the adjustable arm islocked and becomes rigid, one or both of first and second occludingmembers 32, 33 can be locked into position in the slots to occlude thesection of artery. The surgeon then completes the bypass procedure,unlocks the occluding members, removes the sutures from the platform,then removes the adjustable arm and platform from the patient.

In those circumstances where an adjustable platform is used, such asthose depicted in FIGS. 3 and 4, it provides an added degree ofadjustability in positioning the platform so that the occluding memberscan be moved into position over the artery. Thus, as depicted in FIG. 4,when positioning the platform, first leg 11 can be moved away from orcloser to second leg 12 so that the occluding members can be moreaccurately positioned over the artery.

In an alternative embodiment of the invention, as depicted in FIGS.24-26, means are provided to further stabilize the epicardium and holdopen the arteriotomy site to better expose the arteriotomy. In thatregard, retractor 90 having loop 91 is provided as a stainless steelwire (or nickeltitanium/Nitinol), further having hooks positioned at thedistal ends of the wire. As depicted in FIG. 25, loop 91 is positionedaround adjustable arm 60 (only partially shown for clarity) with hooks92 embedded in the heart muscle 93 or epicardium. The arteriotomy site94 is thus fully opened and stabilized for the surgeon to performarteriotomy 95 on the artery. Wire 90 can be shaped or fashioned intovirtually any configuration so that it functions to allow hooks 92 topenetrate the heart muscle and provide a fully exposed and stabilearteriotomy site. Alternatively, as shown in FIG. 26, retractor 90 canbe bent to slide through slot 96 in the platform and further bent sothat hooks 92 hold open the arteriotomy site in the manner depicted.Retractors similar to those depicted in FIGS. 24-26 are commerciallyavailable, for example, in plastic surgery applications, and are soldunder various tradenames including Parsonnet Retractor, available fromPilling Weck, Inc., Research Triangle Park, N.C.

Other embodiments of retractors for use with the present invention tohold back the epicardium can include a pair of jaws attached to wire 90,similar to a clothespin, which would attach to the epicardium. Also,retractor 90 can be advanced and retracted into position by a ratchetingmeans, such as a rack and pinion or a zip tie. A rack and pinion meanscan include ratcheting to tension retractor 90, but which requires aone-eighth or one-quarter turn to release the tension on retractor 90.Further, loop 91 can provide a tension force to hooks 92 if it is formedfrom, for example, stainless steel that has a resiliency or a tensioningloop 91. Portions of retractor 90 might be annealed so that it is moremaneuverable, yet still retaining the tensioning properties.

In a further alternative embodiment, as depicted in FIGS. 27-29,alternative means for occluding the artery are provided. Referring toFIGS. 27, occluding members 32, 33 are attached to legs 11, 12 ofplatform 10. The occluding members include positioning arms 32A, 33A,which are configured so that the occluding members can easily bepositioned over an artery or the epicardium just above the artery. Thus,positioning arms 32A, 33A are formed from a malleable wire, or similarmaterial, so that they can be bent in order to more easily positionoccluding members 32, 33. The positioning arms should be stiff enough sothat as the occluding members are compressed onto the artery or theepicardium above the artery, they will remain in place by occluding theartery until moved by the surgeon.

Similarly, an alternative means for occluding the artery is depicted inFIGS. 28-29, in which a portion of platform 10 is depicted, with leg 11providing support for movable carriage 100. The movable carriage slidesover leg 11 and is retained thereon by sliding along carriage slot 101.The movable carriage includes an occluding member retainer 102, which isconfigured for receiving first and second occluding members 32,33, asherein described. As depicted in FIG. 29, occluding member 32 isconfigured for vertical movement within retainer 102. In use, carriage100 is used to position occluding member 32 over an artery or theepicardium directly above the artery. In use, carriage 100 is used toposition occluding member 32 over an artery or the epicardium directlyabove the artery. Thereafter, occluding member 32 is pressed intocontact with the artery or epicardium above the artery, and tab 41 isthen twisted 90° by the surgeon's fingers or using forceps so that theoccluding member is temporarily locked or wedged in retainer 102. Afterthe bypass procedure is completed, tab 41 is then twisted 90° therebyreleasing occluding member 32 from occluding the artery.

While a particular form and use of the invention has been illustratedand described, and particular dimensions and materials of manufacturehave been disclosed, it will also be apparent to those skilled in theart that various modifications can be made without departing from thespirit and scope of the invention. Accordingly, it is not intended thatthe invention be limited except by the appended claims.

What is claimed is:
 1. Apparatus for stabilizing the epicardium of theheart, comprising:a member having a surface, disposed for contacting theepicardium of the heart, and a structure for selectively engaging themember with the epicardium to stabilize the epicardium during engagementof the member with the epicardium.
 2. Apparatus according to claim 1including an occluding member on a surface of the member disposed toengage an artery or epicardium above the artery for occluding the arteryduring engagement of the member with the epicardium.
 3. Apparatusaccording to claim 1 in which the member is malleable to facilitate theshaping thereof substantially to the contour of the epicardium engagedthereby.
 4. Apparatus according to claim 1 in which a portion of thesurface of the member disposed to engage the epicardium includes aconcave portion configured to span a portion of the epicardium withoutoccluding an artery.
 5. Apparatus according to claim 1 including asupport mechanism attached to the member from fixed position relative tothe member and having selectively flexible coupling therebetween forfacilitating adjustment of the position of the member in engagement withthe epicardium, and for facilitating selective rigid retention of themember in the selected position against the epicardium for thestabilization thereof under compressive force applied to the member viathe support mechanism.
 6. Apparatus according to claim 5 in which thesupport mechanism includes a locking mechanism is operable in unlockedconfiguration to provide the flexible coupling, and in lockedconfiguration to provide the rigid retention of the member against theepicardium.
 7. A method for stabilizing the heart with a memberpositionable relative to a surface of the heart, the methodcomprising:contacting the epicardium of the heart at a selected locationthereon with the member; selectively occluding a section of artery bycontacting the member with the epicardium; performing a medicalprocedure at a location on the heart relative to the occluded artery;releasing the member from contact with the epicardium; and terminatingocclusion of the artery.
 8. The method of claim 7 in which the memberincludes an adjustable support, and the method comprises:positioning themember in contact with the epicardium during operation of the adjustablesupport in flexible configuration; and supporting the member in theposition on the epicardium during operation of the adjustable support inrigid configuration.